Also, I don't think we're seeing any more things weakening Double Team. DT was a valid and strong strategy in early GS (before DT clause was common). GF already nerfed it in RS, introducing Keen Eye and stuff like that (amongst others on Skarmory, THE pokemon of GSC) as well as Shock Wave, Aerial Ace, etc. After that, we even got Trick in OU and Machamp. But yeah, well, perhaps they gonna weaken it a bit again.
Yeah, I'm thinking they'll add a but more to deal with it.
Another "No Guard" Pokemon is possible (let this one know Zap Cannon :P) or better never-miss moves.
One thing though, Keen Eye doesn't help against DT because while it prevents accuracy reduction (from say Sand Attack) it doesn't stop your opponent from raising its own evasion.
I think the reason GF nerfed Regigigas so much was mainly because they didn't realize how much normal typing sucks. Consider this: If Regigigas was Steel, it could easily be viable in OU with 110/110/110 defenses and some common (incl. dragon) resistence. But with normal typing, it has no good switch-ins and can be poisoned. Under this conditions, having no reliable recovery hurts much. I still hope, they give it at least Rest.
Additionally, I think most people expect the wrong thing from Regigigas: It's not a sweeper that needs a lot of support. Regigigas is a wall that cannot be outstalled.
I agree. It's defenses are great regardless of Slow Start so it's better to play to those strengths.
Obviously, if your opponent gives you too much time they'll be battered by hits from one of the highest attack stats in the game.